The use of an array of disks for computer-based data storage is known in the art. One category of disk arrays is referred to as Redundant Array of Inexpensive Drives (RAID). Within a RAID system, varying levels of data storage redundancy are utilized to enable reconstruction of stored data in the event of data corruption or disk failure. These various types of redundant storage strategies are referred to as RAID levels. RAID data storage is discussed in detail in U.S. Pat. No. 5,392,244, which is incorporated herein by reference.
One RAID storage method involves storing two or more complete sets of the same data, with each complete data set stored on one or more different disks. This strategy is generally considered a ‘high’ RAID level (i.e., RAID level one), and provides relatively fast access to the stored data due to simultaneous reading of each data set, as well as complete reconstruction of a redundant data set in the event that one of the data sets is corrupted or otherwise damaged. Due to the complete redundancy of all stored data, this RAID level is relatively space-intensive (i.e., increased media count).
Another RAID storage method, usually considered a ‘low’ RAID level (i.e, RAID level five), is typically utilized when data storage space is at a premium, such as when a plurality of different data sets are being managed. This RAID level utilizes a parity data set to enable the reconstruction of a corrupted data set. This RAID level provides relatively efficient storage (i.e., reduced media count), but requires that reconstruction of a corrupted data set be performed before that data set may be accessed. Furthermore, since only a single instance of any given data set is stored, access is relatively slow compared to the higher RAID level described above (i.e., it is not possible to simultaneously access different parts the same data set).
Therefore, a RAID management system capable of optimizing RAID data types while ensuring future storage space is desired.